[llvm] [WebAssembly] Replace Reachability with SCCs in Irreducible CFG Fixer (PR #179722)

[Kamil Jakubus via llvm-commits]

jkbz64 wrote:

> Might end up being less optimized given our constraints/assumptions.

Roughly tried it out for compiling my grammar that used to take hours/use a lot ram and the performance difference seems marginal/unnoticeable, nice catch.

https://github.com/llvm/llvm-project/pull/179722